I just ran across this today. It's no surprise, but it is interesting that it has been proven in a scientific study. Of course, Karl Rove did his study about how to control the American public through fear long before the Cornell study was done.

ITHACA, N.Y. -- When the federal government issues a terrorist warning, presidential approval ratings jump, a Cornell University sociologist finds. Interestingly, terrorist warnings also boost support for the president on issues that are largely irrelevant to terrorism, such as his handling of the economy.

Robb Willer, assistant director of the Sociology and Small Groups Laboratory at Cornell and a doctoral candidate in sociology who expects his Ph.D. in May 2005, tracked the 26 times that a federal government agency reported an increased threat of terrorist activity in the United States between February 2001 and May 2004. He also tracked the 131 Gallup Polls that were conducted during the same period. He then conducted several time-series and regression analyses on the relationship between government-issued terror warnings and Gallup Poll data on approval ratings of President George W. Bush.

"Results showed that terror warnings increased presidential approval ratings consistently," says Willer. "They also increased support for Bush's handling of the economy. The findings, however, were inconclusive as to how long this halo effect lasts."

When Willer linked the warnings to presidential ratings from 2001 to 2004, he found that each terror warning prompted, on average, a 2.75 point increase in the president's approval rating the following week.